Watch Rob Murphy's report
Young cafe worker Mary Bastholm from Gloucester is thought to be one of the victims of the serial killer Fred West.
Police are currently digging up the cafe where the 15-year-old worked after anomalies were found in the basement by an ITV documentary team.
Mary went missing on Saturday 6 January 1968. She was on her way to visit her boyfriend but never arrived. Despite mass searches and even divers being brought in, no trace of her was found. She was last seen waiting for a bus outside the Avenue Hotel.
Two years on from her disappearance, her family spoke to ITV, convinced that something had happened to her. The reporter, Alan Jones, also interviewed Mary's boyfriend.
This is what they said, 50 years ago.
Mary's mother, Doreen Bastholm, described the evening her daughter disappeared. She said: "She went out between 10 and a quarter past seven with a carrier bag with a Monopoly set in to catch the 25 past seven bus at the end of Tuffley Avenue and that was the last we saw of her."
Mary's boyfriend Tim Merret had been due to meet her off the bus but she never arrived.
When did you suspect something was wrong?
Alan Jones asked Tim when he suspected something was wrong. He said: "Well, as soon as she wasn't on that - and she wasn't on the 8.30pm bus. So I went back home and then asked my sister if she'd run me up to Mrs Bastholm's.
What do you think could have happened that night?
Mary's father Christian Bastholm said: "Well it's rather difficult to say but one thing, I'll always say this, she didn't go away on her own. A free young girl like that to evade the police for so long. Well, she'd have to be a master at the game, wouldn't she?"
"Well personally myself I think she took a lift from someone she knew. This could have been someone that perhaps came into the cafe..."
The cafe Christian Bastholm was referring to was the Pop-In cafe where Mary worked. Fred West was a regular customer and the building - now called the Clean Plate - is at the centre of a painstaking investigation. Forensic officers and archaeologists are digging up the basement in case Mary's remains are hidden there.
50 years ago, police said they had a 'completely open mind' about Mary's disappearance.
What would you say to Mary if she could hear you?
Doreen Bastholm said: "Please come home or get in contact with us."
Christian Bastholm said: "I think she'd immediately do it. She was a very emotional girl. I don't think she'd have kept us this long. Even if she had run away by herself or with someone else, I think if she'd had the opportunity she'd have communicated with us before now."
Are you still hopeful that Mary will turn up?
Mary's boyfriend Tim Merret said, "Oh yes... Well, when I don't still know I just hope."